Gene Therapy Shows Promise in Treating Rare Eye Disease

Scientists have improved the vision of a small number of patients suffering from a rare and incurable eye disease by replacing a defective gene with a healthy one—a boost for a technique known as gene therapy.

The patients have choroideremia, a degenerative disease caused by defects in a single gene that leads to blindness and affects 1 in 50,000 people. In an early-stage trial published Wednesday in the Lancet, the researchers used a deactivated virus to safely ferry billions of healthy, lab-made versions of the gene into...